Is jealousy natural? Cancer is natural, and so is our appendix. Is jealousy instinctive? Even if we assume it so, our ability to adapt beyond genetic limits is also natural. But anthropology gives us many examples of human sexuality beyond monogamy. Perhaps many of our beliefs about sex are arbitrary based on where and when we were born.
We do not grow new eyes; we create glasses and laser-surgery to make up for genetic flaws. Perhaps possessiveness with lovers is a flaw like being near-sighted.
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